howell



(No Model.) 2 Sheets-Sheet 1.

J. W. HOWELL.

v ELECTRICAL DISTRIBUTION. I No'. 372,797. Patented Nov. 8,1887.

w I /2 5 C i E A (No Model.) 2 SheetsSheet 2. J. W. HOWELL.

I ELECTRICAL DISTRIBUTION.

No. 372,797. Patented Nov. 8, 1887.

UNITED STATES PATENT OFFICE.

JOHN W. HOvV ELL, OF NEW BRUNSWICK, NEIV JERSEY.

ELECTRICAL DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 372,797, dated November 8, 1887.

Application filed March 4, 1887. Serial No. 229,685. (No model.

To aZZ whom it may concern.-

Be it known that I, J OHN W. HownLL, of New Brunswick, in the county of Middlesex and State of New Jersey, have invented a certain new and useful Improvement in Systems of Electrical Distribution, of which the following is a specification.

My invention relates to systems of electrical distribution of that character in which two or more feediug circuits extend from a source of supply to a system of mains or lightingcircuits with which the electric lamps or other translating devices to be supplied are connected.

Heretofore in such systems it has been usual to extend pressure-wires or indicating-circuits from the outer terminals of each of the feeders to the central station,where indicators are connected with them of such character as will show the pressure or potential at the feeder'terminals. In accordance with these indications the resistance of the different feeders is varied, so that their pressures are all maintained alike, and the same constantpressure is maintained in all parts of the district supplied.

The object of my invention is to economize in and simplify such a system by doing away with most of the indicatingcfrcuits, while at the same time providing efficient and accurate means of indication, for the purpose mentioned. In accomplishing this object I employ an indicating-circuit and an absolute indicator in connection with one of the feedingcircuits, and in this way am enabled to maintain the right pressure constant on this feeder, which thus forms a standard feeder, and I p rovide differentially-operating com parativeindicators which compare the drop or loss of potential in a definite part of the resistance of this standard feeder with the drop in a corresponding part of each of the other feeders.

My invention is illustrated in the accompanying drawings, in which Figure l is a diagram illustrating the prin ciple of the invention; Fig. 2, a diagram of a two-wire system or part of a system of electrical distribution embodying said invention; Fig. 3, a similar diagram showing a threewire system, and Fig. at a diagram showing my invention in a system in which the feeders are each composed of two or more strands.

Referring first to Fig. 1, 1 2 represent the omnibus wires at the central station. 3 at repsent the system of mains or lighting conductors, and 5 6 and 7 8 are feeding circuits extending from the omnibus conductors to different points on the system of mains. The feeding-circnit 5 6, being the standard circuit, has an indicating-circuit, 9 10, extending from the outer terminals of its conductors to the central station,where an absolute indicator,A, of electro-motive force is connected with such circuit, the indicator being preferably of the kind set forth in my Patent No. 339,058, dated March 30, 1886.

B represents a coil of wire or other fixed resistance included in one of the conductors of the standard feeder 5 6. G is a similar coil included in a conductor of the feeder 7 8. These coils have the same ratio to the total resistance of the respective feeding-circuits, which include them, so that the loss in the fixed resistance of one feeder bears the same ratio to the total loss in that feeder as the 7 5 loss in the fixed resistance of the other feeder does to that feeders total loss.

Ashunt-circuit,1l 12, is formed around the fixed resistance B, and a shunt, 13 14., around the resistance 0, and each of these shunts ineludes part of the coils of a galvanorneter, D, the two sets of coils being wound so as to oppose each other and to be equal in their effect when they have the same current. The cur rent in each set of galvanometer-coils will depend upon the loss in potential in the resistance around which it is shunted, and as in the two circuits the loss in the fixed resistance is in the same proportion to the loss on the whole feeder, when the galvanometer-needle stands c at zero it indicates that the loss is the same on both feeders, and therefore that the potential at their outer terminals is the same; and since the potential on 5 6 is kept right constantly by reference to indicator A the variations of 5 the galvanometer-needle in one direction or the other willindicate whether the pressure on 7 8 is at any time greater or less than that on 5 6. Each feeder of the system being provided with a fixed resistance with a shunt around it,

including coils of a galvanometer having differential coils in a shunt around the fixed resistance in the standard feeder, the pressure on each feeder is constantly indicated by comparison with that of the standard feeder.

When adjustable resistances are introduced into the feeders for regulating their pressure separately, the ratio between the fixed resistance and the total feeder-resistance becomes variable, and the loss on the fixed resistance is no longer an index to the total loss on the feeder. Additional elements have therefore to be provided in order to insure accurate indications, as shown in Fig. 2. Here the standard feeder 5 6 has an adjustable resistance, E, and the feeder 7 8 has an adjustable resistance, F, in addition to the fixed resistances. Each feeder is provided with one of these adjustable resistances, which are known as equalizers, theirpurpose being to maintain an equal pressure throughout the system.

Around the adjustable resistance E, I form a shunt-circuit, 11 15, and around resistance F ashunt-circuit, 13 16. Each of these shunts includes coils of the differential galvanometer G, such coils opposing each other, but each acting similarly to the coils from the fixed resistance on the same feeder. The coil shunted around the variable resistance is proportioned to that around the fixed resistance according to the ratio of the fixed resistance to the total resistance of the feeder. For instance, if the fixed resistance is one-fiftieth of the resistance of the whole feeder without any equalizer, then when the equalizer 'is in circuit the total feeder loss is the loss in the equalizer plus :fifty times the loss in the fixed resistance.

Then if each of the coils shunted around an equalizer has one-fiftieth as many turns of wire as each of the fixed-resistance shunt-coils, then as the coil around the fixed resistance is fifty times as effective as the one around the equalizer, their combined effect indicates the loss in the equalizer plus fifty times the loss on the fixed resistance, which equals, as just explained, the totalloss on the feeder. Thus we make the coils around the fixed resistance as many times as effective as those around the equalizer as the multiple of the fixed resistance into the total resistance of the feeder.

By the arrangement thus described, and shown in Fig. 2, and which may of course be applied to any desired number of feeding-circuits, the losses can be readily and accurately compared, and thus the potentials at the feeder terminals may be constantly indicated and kept at the standard by the adjustment of the equalizers.

Fig. 3 represents a three-wire system. 1 a 2 are the omnibus wires. 3 c 4 are the mains. 5 c 6 is the standard feeder, and 7 c 8 is another feeder. 9 c 10 is the indicating-circuit for the standard feeder connected with absolute indicators A A, one for each side of the system.

'In a three-wire system the pressure or potential between the neutral wire and each of the outside wires is regulated separately. In this case the pressure on the same side of two feeder ends is the same when the algebraic sum of the losses in the outside wire and neutral wire is the same in both feeders. In taking this algebraic sumitis theoretically considered that currents flowing outward from the station in either outside wire are positive, while in the neutral such currents are negative. What has to be done, therefore, in carrying out my invention is to show when the algebraic sum of the losses is the same in the same side of two feeders. If there are no equalizers, this may be done by a four-coil galvanometer having one set of coils shunted arounda fixed resistance in the positive wire of the standard feeder, another around a fixed resistance in the corresponding wire of the other feeder, and a coil around a fixed resistance in the neutral wire of each feeder. These must be so connected that the coils from the same feeder act oppositely when currents are flowing in the same direction through the two wires of this feeder, and the coils from the outside wires of the same polarity in the two feeders are wound to act oppositely when currents are flowing in the same direction in these wires. A galvanometer is similarly connected between the negative sides of thetwo feeders. When equalizers are used, each galvanometer must have two more coils shunted around the equalizers. These coils are less effective than the other four coils, in the same way as explained with reference to the two-wire system.

In Fig. 3, G G are the sixcoil galvanometers. Galvanometer G has a coil in a shunt around the equalizer H in the positive conductor of standard feeder 5 c 6, another coil in a shunt around the fixed resistance I in the same conductor, two coils around, respectively, the equalizer H and fixed resistance I in the feeder 7 c 8, a coil around the fixed resistance K in the neutral wire of the standard feeder, and a coil around the fixed resistance K in the neutral wire of the other feeder. Galvanometer G is similarly connected between the negative sides of the two feeders, having coils shunted around resistances K, K, H, H 1 and 1 respectively. The galvanometer-coils are wound and proportioned relatively, as has been explained. All the other feeders, if there be any, are similarly connected through sixcoil galvanometers with the standard feeder. By this means the losses in definite parts of the feeders are compared and their pressure is kept at the standard by the adjustment of the equalizers.

In Fig. 4 is shown a two-wire system with each feeder 5 6 and 7 8 composed of two or more parts or strands of wire, the regulation of pressure being accomplished by the insertion or removal of the strands from the circuits by switches M M, instead of by adj ustable resistances, such as before described. Such a system is shown and described in my Patent No. 842,748, dated May 25, 1886. The

absolute indicators are omitted from this figure because of lack of space. In such a system a galvanometer, N, with four equal coils may be used to show whether or not the losses on two feeders are the same. A fixed resistance, 0, is put in the strand d of each feedingconductor which remains longest in circuit, or is always in circuit when the feeder is in use. The loss on this strand is always equal to the totalloss in the conductor,no matter how many strands are in use, and the loss in the fixed resistance 0 will therefore be an index to the loss in the whole conductor.

By connecting the four coils of the galvanometer N, respectively, around the four fixed resistances of the two feeders, the two coils from one feeder acting together and oppositely to the two coils from the other feeder, I compare the sum of the losses in the two sides of one feeder with the sum of the losses in the two sides of the other feeder, and am thus enabled to keep these sums the same, and thus keep the pressures at the ends of the feeders the same, the standard feeder being provided, as before, with the absolute indicator A. In the arrangement shown,where both conductors of each feeder are regulated, each fixed resistance O is placed in the strand of its feeder which remains longest in circuit. If only one conductor of each feeder is composed of strands and regulated thereby, the fixed resistance is placed in that strand which is always in circuit, while in the opposite conductor the resistance is inserted directly, as in the previously-described cases. This samemode of arrangement and connection for the indicators may be used also with the feeding-conductors shown and described in an application filed by me of even date herewith, Serial No. 229,686-thatis to say, conductors formed each of two parts or strands, one much smaller than the other, the smaller one containing the fixed resistance and the larger one an adjustable re sistance or equalizer. It will be seen that the small conductor is the strand remaining continually in circuit, while the conductor containing the adjustable resistance corresponds with the number of strands whose resistance is regulated by placing more or less of the strands in circuit.

What I claim is- 1. The combination, with two feeding circuits of a system of electrical distribution, of a fixed resistance in each of said feeding-circuits, and an indicating device affected differentially by the losses in potential in said fixed resistances, substantially as set forth.

2. The combination,with the standard feeding-circuit of a system of electrical distribution, of an indicating device connected therewith for indicating its potential absolutely, a fixed resistance in said standard circuit, another feedingcircuit having a fixed resistance, said resistances bearing the same ratio to the total rcsistances'of their respective circuits, and an indicating device affected d ff entially by the losses in potential in said fixedm resistance, substantially as set forth.

3. The combination, with two feeding-circuits of a system of electrical distribution, of a shunt around a fixed resistance in each of said circuits, and a differential galvanometer having a portion of its coils in each of said shunts, substantially as set forth.

4. The combination, with two feeding-circuits of asystem of electrical distribution, of a fixed resistance and an adjustable resistance in each of said circuits, a shunt around each fixed resistance, and a shunt around each adjustable resistance, and a galvanometer having a part of its coils in each of said shunts, the coils from the same feeder being wound to act together and oppositely to those from the other feeder, substantially as set forth.

5. The combination, with two feeding-circuits of a system of electrical distribution, of a shunt around a fixed resistance in each of said circuits, a differential galvanometer having a portion of its coils in each of said shunts, and means for adjusting the resistance of each of said feeding-circuits, substantially as set forth.

6. The combination, with two feeding-circuits of a system of electrical distribution, ofa fixed resistance in each side of each of said circuits, a shunt around each of said resistances, and a differential galvanometer having portions ofits coils in each of said shunts, the coils from the same feeding-circuit being wound to assist each other, and those from like conductors of the two circuits opposing each other, substantially as set forth.

7. The combination, with two threewire feeding-circuits of a three-wire system of electrical distribution, of a fixed resistance in each of the three conductors-positive, negative, and neutral-of each of said circuits,a differential galvanometer having coils in shuntsaround the resistances in the positive and neutral condutors, respectively, of said circuits, the coils from like conductors being wound to oppose one another, and for each feeder the coil from the neutral conductor opposing that from the positive conductor when the neutral. current is flowing outward and assisting it when said current is flowing inward, and another galvanometer having coils similarly arranged in shunts from the neutral and negative wires of the two circuits, substantially as set forth.

8. The combination, with two three-wire feeding-circuits of a three-wire system of electrical distribution, of a fixed resistance in each of the three conductors-positive, negative, and neutral-of each of said feeding-circuits, an adjustable resistance in the positive conductor, and another in the negative conductor of each of said circuits, a differential galvanometer having coils in shunts, respect ively, around the fixed resistances in the positive and neutral conductors, and the adjustsisting those around fixed resistances in the 10 same conductor, and another galvanometer having coils similarly arranged in shunts from the neutral and negative wires of the two circuits, substantially as set forth.

This specification signed and witnessed this 28th day of February, 1887.

JOHN W. HOWELL.

Witnesses:

FRANCIS E. J ACKSON, GEORGE F. MORRIsON. 

